Synthesis of new functionalized aziridine-2-and azetidine-3-carboxylic acid derivatives of potential interest for biological and foldameric applications

short synthesis of alkyl 2-(bromomethyl)aziridine-2-carboxylates and alkyl 3-bromoazetidine-3-carboxylates was developed involving amination, bromination, and base-induced cyclization of alkyl 2-(bromomethyl)acrylates. The aziridines are the kinetically favored cyclization products and could be transformed into 3-bromoazetidine-3-carboxylic acid derivatives via thermal isomerization. The new small-membered azaheterocyclic alpha- and beta-amino acid derivatives contain a bromo-substituted carbon center as a useful moiety for functionalization. Transformation of these functionalized azaheterocycles via nucleophilic substitution with carbon, sulfur, oxygen, and nitrogen nucleophiles and via elaboration of the amino and carboxyl group provided a broad range of new conformationally constrained aziridine-2- and azetidine-3-carboxylic acid derivatives, which are of interest from a biological point-of-view as well as for applications in the field of foldamers

New PEO-IAA-Inspired Anti-Auxins: Synthesis, Biological Activity, and Possible Application in Hemp (Cannabis Sativa L.) Micropropagation

Auxins play an important role in plant physiology and are involved in numerous aspects of plant development, such as cell division, elongation and differentiation, fruit development, and phototropic response. In addition, through their antagonistic interaction with cytokinins, auxins play a key role in the regulation of root growth and apical dominance. Thanks to this capacity to determine plant architecture, natural and synthetic auxins have been successfully employed to obtain more economically advantageous plants. The crosstalk between auxins and cytokinins determines plant development and thus is of particular importance in the field of plant micropropagation, where the ratios between these two phytohormones need to be tightly controlled to achieve proper rooting and shoot generation. Previously reported anti-auxin PEO-IAA, which blocks auxin signalling through binding to TIR1 receptor and inhibiting the expression of auxin-responsive genes, has been successfully used to facilitate hemp micropropagation. Herein, we report a set of new PEO-IAA-inspired anti-auxins capable of antagonizing auxin responses in vivo. The capacity of these compounds to bind to the TIR1 receptor was confirmed in vitro by SPR analysis. Using DESI-MSI analysis, we evaluated the uptake and distribution of the compounds at the whole plant level. Finally, we characterized the effect of the compounds on the organogenesis of hemp explants, where they showed to be able to improve beneficial morphological traits, such as the balanced growth of all the produced shoots and enhanced bud proliferation

Synthesis and reactions of 1-hydroxy-9,9a-dihydro-1H-imidazo[1,2-a]indol-2(3H)-ones

In Session: Next Generation Networks: NXG-05: Switching and Routing-I: article no. NXG05-6A hybrid electronic/optical packet switch consists of electronically buffered line-cards interconnected by an optical switch fabric. It provides a scalable switch architecture for next generation high-speed routers. Due to the non-negligible switch reconfiguration overhead, many packet scheduling algorithms are invented to ensure performance guaranteed switching (i.e. 100% throughput with bounded packet delay), at the cost of speedup. In particular, minimum delay performance can be achieved if an algorithm can always find a schedule of no more than N configurations for any input traffic matrix, where N is the switch size. Various minimum delay scheduling algorithms (MIN, α i-SCALE and QLEF) are proposed. Among them, QLEF requires the lowest speedup bound. In this paper, we show that the existing speedup bound for QLEF is not tight enough. A new bound which is 10% lower than the existing one is derived. © 2006 IEEE.published_or_final_versionProceedings of the Global Telecommunications Conference, 2006 (GLOBECOM 2006), San Francisco, CA, USA, 27 November - 1 December 200

Synthesis of alkyl 3-chloroazetidine-3-carboxylates via regioselective ring transformation of alkyl 2-(bromomethyl)aziridine-2-carboxylates

The synthesis of alkyl 3-chloroazetidine-3-carboxylates was developed by ring transformation of alkyl 2-(bromomethyl)aziridine-2-carboxylates utilizing ring opening with hydrochloric acid at the more sterically hindered carbon atom of the aziridine ring and subsequent base-promoted ring closure

Cyclization of nitrospirobenzopyrans to bridged benzoxazepino[3,2-a]indoles

Condensation of 1-substituted 1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones with 5-nitrosalicylaldehyde afforded 1'-[(N-monosubstituted carbamoyl)methyl]indoline nitrospirobenzopyrans. Treatment of the latter with strong base led to the formation of a mixture of cis/trans-5a,13-methano-1,3-benzoxazepino[3,2-a]indoles. Results of semiempirical calculations gave evidence that such a transformation of nitrospirobenzopyrans to bicyclic indole derivatives could proceed via a single transition state, where the negatively charged carbon atom attacks the vinylic double bond of the spiropyran system

Synthesis and Ring Opening of Alkaloid-Type Compounds with a Novel Indolo[2,3-c][2]benzazepine Skeleton

Alkylation of the magnesium salts of 2,3-disubstituted indoles with 2-bromomethylbenzonitrile gave 3-(2-cyanobenzyl)-3H-indole derivatives. Reduction of the cyano group of N-methyl 3-(2-cyanobenzyl)-3H-indolium salts afforded previously unreported indolo[2,3-c][2]benzazepines, while acid hydrolysis gave the corresponding indolo[2,3-c][2]benzazepinones. The action of strong protonic acids on indolo[2,3-c][2]benzazepines causes opening of the benzazepine ring annelated to the indole system to form 3H-indolium S salts